Ancient Antarctic Ice Could Reveal Clues to Earth’s Climate 1.5 Million Years Ago

Swiss scientists from the University of Bern are hoping that a 3 km long cross-section of Antarctic ice could reveal new information about climate change throughout the Earth’s history. Over the ages, built-up snow and air have been compressed into thick layers of ice that serve as a permanent record of global temperatures and the amount of greenhouse gasses in the atmosphere. Researchers believe that a new expedition would be able to extract ice cores dating back 1.5 million years – almost twice as far back as the current oldest samples, which extend 800,000 years.

The new ice cores may be the key to unlocking a major shift in Earth’s history. The planet has gone through a number of periods of warming and cooling over the ages. For the past 900,000 years, ice ages have come and gone in regular 100,000 year cycles. But before this period, the cycles were much shorter, occurring roughly every 40,000 years instead. So far, researchers have been unable to confirm the reason for this shift, but it may have to do with the amount of carbon dioxide in the atmosphere.

Collecting such a detailed sample of Antarctic ice has proved difficult in the past. In the thickest areas, geothermal heating near the base of the ice gradually melts away the oldest layers. This limits the age of the ice that scientists are able to obtain. Horizontal movements can also cause the ice to shift so that the oldest annual layers to get jumbled together.

The Swiss team has been hard at work identifying potential drill sites which might provide the right conditions for longer-range samples. In the next 3-5 years, it should be possible to actually begin drilling the ice in an expedition with an estimated cost around 50 million Euros. It’s currently still in the planning stages, but the researchers have published their research on potential drill sites in the journal Climate of the Past. You can read the results of their research here.